Drug interactions- summary-

Antacids +Fosamprenavir -
coadministration decreased Cmax and AUC of fosamprenavir

Anticonvulsants eg carbamazipine, phenobarbital + fosamprenavir-
fosamprenavir may be less effective on coadministration. Use with caution

Fosamprenavir + carbamazepine-
carbamazepine levels elevated

Azole antifunfangals eg itraconazole, ketoconazole + fosamprenavir-/
fosamprenazole + Azole antifunfangals eg itraconazole, ketoconazole-
coadmin may lead to increase in ketoconazole or itraconazole adverse reactions.
Monitor fosamprenavir toxicity and adjust dose

Contraceptives oral eg ethinyl estradiol/norethindrone + fosamprenavir/
fosamprenavir + Contraceptives oral eg ethinyl estradiol/norethindrone -
coadmin may decrease fosamprenavir AUC and lead to loss of virologic response.
Alternative methods of nonhormonal contraception recommended

Delavirdine + fosamprenavir/ Fosamprenavir + delavirdine -
coadmin may  increase fosamprenavir concentration. leading to loss of virologic
response. Coadmin contraindicated.

CYP450 3A4 inhibitors eg clarithromycin + fosamprenavir -
use with caution. May lead to increased fosamprenavir concentrations

Dexamethasone + fosamprenavir-
fosamprenavir may be less efective due to decreased fosamprenavir concentration.
Use with caution

Efavirenz + fosamprenavir /Fosprenavir + efavirenz-
coadim lead to decreaed fosamprenavir concentrations. Additional 100mg/day
( 300mg total ) of ritonavir is recommended
 

HIV infection

Adverse reactions-

CNS -  fatigue  2%    headache  2%

Dermatologic - rash  7%

GI -    abdominal pain  1%    diarrhea  4%  nausea 6%  vomiting 2%

Hypersensitivity reactions-

Special precautions-

Skin reactions- severe orlife threatening skin reactions inculding stevens- Johnson syndrome
reported. Discontinue treatment if  severe skin reactions take place

Hepatic toxicity - use of fosamprenavir with ritonavir at higher than recommended dosage
may result in transaminase elevation. Thes doses should not be used.

Lipid elevations- treatment with fosamprenavir + ritonavir resulted in increase in concentration
of triglycerids. Perform triglycerids and cholesterol testing prior to starting treatment with
fosamprenavir + ritonavir

Hepatic function impairment- excercise caution when administering fosamprenavir to patients
with hepatic function impairment.

Pregnancy- Use fosamprenavir + retonovir in pregnant women with  caution.

Lactation - instruct mothers not to breast feed if they are receiving fosamprenavir

Children- the adverse reaction profile in children was similar to adults. vomiting was
frequent in children than in adults.

Monitoring- perform triglycerideand cholesterol testing prior to initiating therapy with
fosamprenavir and at periodic intervals thereafter.

Indication-

HIV infection

Dosage-
Recommended dose of fosamprenavir alone or in combination with ritonavir is 1400mg
twice daily (without retonavir )
fosamprenavir 1400mg once daily + ritonavir 200mg once daily
fosamprenavir 700mg twice daily + ritonavir 100mg twice daily

1. Inform patients that fosamprenavir is not cure for HIV infections

2. Advice  patients to the drug every day as prescribed by the doctor.

3. Advice patients not to alter or change the dosage  or discontinue without informing
   the doctor.

4. Instruct patients receiving hormonal contraceptives to use alternative contraceptive
   during therapy measures with fosamprenavir, becuase hormonal levels are altered.

5. Inform patients that redistribution or accumulation of body fat may occur in patients
   receiving antiretroviral therapy

Pregnancy-
Use fosamprenavir + retonovir in pregnant women with  caution.

Lactation -
Instruct mothers not to breast feed if they are receiving fosamprenavir

Children-
The adverse reaction profile in children was similar to adults. vomiting was
frequent in children than in adults.